The present invention relates to a manufacturing method of a micro-lens, a manufacturing method of a solid-state image pickup device and a solid-state image pickup device, in particular, a manufacturing technology of a micro-lens that is used in various kinds of optical devices.
A micro-lens (including an array of micro-lenses) is provided to an optical device such as a solid-state image pickup device and a liquid crystal display device. For instance, when a micro-lens is provided to a solid-state image pickup device, it is general that an organic film such as a color resist is formed at the upper-most layer followed by forming a micro-lens according to a thermal reflow method.
However, there is a problem in that an organic film is less resistant to heat. A heat-resistant micro-lens can generate various advantages. For instance, when a micro-lens is formed to a solid-state image pickup device by use of an organic film, it is difficult to form the lenses in the middle of process and to bring the lenses nearer to the respective photodiodes. However, it can be realized by use of an inorganic film.